ok, a guy in my area is selling a 5.7L vortec 350 with 68,000 out of his wrecked 2003 1500 truck for 200 bucks..thats pretttty cheap..question is they must have put a different motor in the truck because they didnt make the 5.7L in 03 for trucks anyway, at least thats what i c on wikipedia..whats the best way to tell what this motor is? casting #s, external visuals? i would do the research myself but i need to go to work and may not have time to do it before i check the motor out..it might be gone before i can do any research. appreciate any insight. i will have someone to help me diagnose the state of the motor when i go hopefully..since it was in a wrecked vehicle etc. are computer/wiring harnesses expensive for an assumingly late model vortec 350 also?

 

Check the VIN. You are right that the 2003 1500 didn't have a 5.7L Vortec. It is likely a 5.3L LM7. Check the intake cover and it probably says "Vortec 5300."

2003 Silverado:

VIN T - LM7 (iron block/aluminum heads)

VIN Z - Flex Fuel L59




If it's really a stock 2003 1500, then it has a 5.3L will is still plenty of motor for you.

 

External visuals are pretty simple. Stamped valve covers, distributor - earlier Gen I. Coil-on-covers, LS-type.

If it is a 5.3, then try to get the harness & PCM with it (and transmission if it's 2WD). $200 isn't too surprising - you can get a good used 5.3 with warranty from the JY's for less than $400.